Organometallics 2005, 24, 769-772
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Synthesis and Characterization of C10H10-Bridged Bimetallic Ruthenium Complexes Sheng Hua Liu,†,‡ Quan Yuan Hu,† Peng Xue,† Ting Bin Wen,† Ian D. Williams,† and Guochen Jia*,† Department of Chemistry and Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, and College of Chemistry, Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, Central China Normal University, Wuhan 430079, People’s Republic of China Received August 16, 2004 Summary: Treatment of RuHCl(CO)(PPh3)3 with (3E,5E,7E)-HCtCCHdCHCHdCHCHdCHCtCH produces [RuCl(CO)(PPh3)2]2(µ-CHdCHCHdCHCHd CHCHdCHCHdCH). The latter complex reacts with PMe3 to give [RuCl(CO)(PMe3)3]2(µ-CHdCHCHdCHCHd CHCHdCHCHdCH), the structure of which has been confirmed by X-ray diffraction. The electrochemical properties of the latter C10H10-bridged complex have been investigated. Introduction There has been much interest in the synthesis and properties of bimetallic complexes with conjugated hydrocarbon ligands bridging metal centers.1,2 Cx and (CH)x are probably the simplest hydrocarbon bridging ligands. The synthesis and properties of bimetallic complexes with Cx bridges have been intensively investigated, and a number of complexes of the type LnM(µCx)M′L′n with x up to 20 and with M or M′ ) Re, Fe, Ru, Pt, Pd, Mn, W, and Rh have been synthesized in recent years.2 In contrast to bimetallic complexes with Cx bridges, the number of bimetallic complexes with (CH)x bridges are still rather limited. Previously reported examples of (CH)x-bridged bimetallic complexes are limited to a few with (CH)2,3 (CH)4,4-6 (CH)5,7 †
The Hong Kong University of Science and Technology. Central China Normal University. (1) (a) Bruce, M. I.; Low, P. J. Adv. Organomet. Chem. 2003, 40, 231. (b) Long, N. J.; Williams, C. K. Angew. Chem., Engl. Ed. 2003, 42, 2586. (c) Paul, F.; Lapinte, C. Coord. Chem. 1998, 178, 431. (d) Bunz, U. H. F. Angew. Chem., Int. Ed. Engl. 1996, 35, 969. (e) Lotz, S.; Van Rooyen, P. H.; Meyer, R. Adv. Organomet. Chem. 1995, 37, 219. (f) Long, N. J. Angew. Chem., Int. Ed. Engl. 1995, 34, 21. (g) Ward, M. D. Chem. Soc. Rev. 1995, 121. (h) Lang, H. Angew. Chem., Int. Ed. Engl. 1994, 33, 547. (i) Beck, W.; Niemer, B.; Wieser, M. Angew. Chem., Int. Ed. Engl. 1993, 32, 923. (2) For recent work on of bimetallic complexes with Cx bridges, see for example: (a) Xu, G. L.; Zou, G.; Ni, Y. H.; DeRosa, M. C.; Crutchley, R. J.; Ren, T. J. Am. Chem. Soc. 2003, 125, 10057. (b) Yam, V. W. W.; Wong, K. M. C.; Zhu, N. Y. Angew. Chem., Int. Ed. 2003, 42, 1400. (c) Bruce, M. I.; Ellis, B. G.; Gaudio, M.; Lapinte, C.; Melino, G.; Paul, F.; Skelton, B. W.; Smith, M. E.; Toupet, L.; White, A. H. Dalton 2004, 1601. (d) Coat, F.; Paul, F.; Lapinte, C.; Toupet, L.; Costuas, K.; Halet, J. F. J. Organomet. Chem. 2003, 683, 368. (e) Jiao, H. J.; Costuas, K.; Gladysz, J. A.; Halet, J. F.; Guillemot, M.; Toupet, L.; Paul, F.; Lapinte, C. J. Am. Chem. Soc. 2003, 125, 9511. (f) Mohr, W.; Stahl, J.; Hampel, F.; Gladysz, J. A. Chem. Eur. J. 2003, 9, 3324. (g) Horn, C. R.; Gladysz, J. A. Eur. J. Inorg. Chem. 2003, 2211. (h) Horn, C. R.; Martin-Alvarez, J. M.; Gladysz, J. A. Organometallics 2002, 21, 5386. (3) (a) Rajapakse, N.; James, B. R.; Dolphin, D. Can. J, Chem. 1990, 68, 2274. (b) Bullock, R. M.; Lemke, F. R.; Szalda, D. J. J. Am. Chem. Soc. 1990, 112, 3244. (c) Lemke, F. R.; Szalda, D. J.; Bullock, R. M. J. Am. Chem. Soc. 1991, 113, 8466. ‡
(CH)6,8,9 and (CH)810 bridges. Related bimetallic complexes of the types LnMdC(OR)CHdCHC(OR)dMLn or LnMdCRRCRdMLn11 and LnMCHdCHArCHdCHMLn12 are also known. In this work, we wish to report the synthesis, characterization, and electrochemical properties of the first (CH)10-bridged bimetallic complexes. Results and Discussion Reactions of RuHCl(CO)(PPh3)3 with HCtCR are known to give RuCl(CHdCHR)(CO)(PPh3)2.13,14 The reaction has been used to prepare bimetallic complexes such as [RuCl(CO)(PPh3)2]2(µ-CHdCHArCHdCH)12 and [RuCl(CO)(PPh3)2]2(µ-(CHdCH)x) (x ) 2,6 3,9 410). Thus, it was reasoned that bimetallic complexes with a C10H10 bridge might be obtained by starting from the reaction (4) (a) Sponsler, M. B. Organometallics 1995, 14, 1920. (b) Etzenhouser, B. A.; Chen, Q.; Sponsler, M. B. Organometallics 1994, 13, 4176. (c) Etzenhouser, B. A.; Cavanaugh, M. D.; Spurgeon, H. N.; Sponsler, M. B. J. Am. Chem. Soc. 1994, 116, 2221. (d) Chung, M. C.; Gu, X.; Etzenhouser, B. A.; Spuches, A. M.; Rye, P. T.; Seetharaman, S. K.; Rose, D. J.; Zubieta, J.; Sponsler, M. B. Organometallics 2003, 22, 3485. (5) Niu, X.; Gopal, L.; Masingale, M. P.; Braden, D. A.; Hudson, B. S.; Sponsler, M. B. Organometallics 2000, 19, 649. (6) Xia, H. P.; Yeung, R. C. Y.; Jia, G. Organometallics 1998, 17, 4762. (7) (a) Xia, H. P.; Jia, G. Organometallics 1997, 16, 1. (b) Xia, H. P.; Yeung, R. C. Y.; Jia, G. Organometallics 1997, 16, 3557. (8) Fox, H. H.; Lee, J. K.; Park, L. Y.; Schrock, R. R. Organometallics 1993, 12, 759. (9) Liu, S. H.; Xia, H. P.; Wen, T. B.; Zhou, Z. Y.; Jia, G. Organometallics 2003, 22, 737. (10) Liu, S. H.; Chen, Y. H.; Wan, K. L.; Wen, T. B.; Zhou, Z. Y.; Lo, M. F.; Williams, I. D.; Jia, G. Organometallics 2002, 21, 4984. (11) See for example: (a) Guillaume, V.; Mahias, V.; Mari, A.; Lapinte, C. Organometallics 2000, 19, 1422. (b) Ferna´ndez, I.; Sierra, M. A.; Manchen˜o, M. J.; Go´mez-Gallego, M.; Ricart, S. Organometallics 2001, 20, 4304. (c) Ulrich, K.; Guerchais, V.; Do¨tz, K. H.; Toupet, L.; Le Bozec, H. Eur. J. Inorg. Chem. 2001, 725. (d) Rabier, A.; Lugan, N.; Mathieu, R. J. Organomet. Chem. 2001, 617, 681. (e) Briel, O.; Fehn, A.; Beck, W. J. Organomet. Chem. 1999, 578, 247. (12) (a) Go´mez-Lor, B.; Santos, A.; Ruiz, M.; Echavarren, A. M. Eur. J. Inorg. Chem. 2001, 2305. (b) Jia, G.; Wu, W. F.; Yeung, R. C. Y.; Xia, H. P. J. Organomet. Chem. 1997, 539, 53. (c) Santos, A.; Lo´pez, J.; Montoya, J.; Noheda, P.; Romero, A.; Echavarren, A. M. Organometallics 1994, 13, 3605. (13) Torres, M. R.; Vegas, A.; Santos, A.; Ros, J. J. Organomet. Chem. 1986, 309, 169. (14) For recent work, see for example: (a) Maruyama, Y.; Yamamura, K.; Sagawa, T.; Katayama, H.; Ozawa, F. Organometallics 2000, 19, 1308. (b) Maruyama, Y.; Yamamura, K.; Nakayama, I.; Yoshiuchi, K.; Ozawa, F. J. Am. Chem. Soc. 1998, 120, 1421. (c) Harlow, K. J.; Hill, A. F.; Welton, T. J. Chem. Soc., Dalton Trans. 1999, 1911. (d) Hill, A. F.; Ho, C. T.; Wilton-Ely, J. D. E. T. Chem. Commun. 1997, 2207. (e) Harlow, K. J.; Hill, A. F.; Welton, T.; White, A. J. P.; Williams, D. J. Organometallics 1998, 17, 1916. (f) Jia, G.; Wu, W. F.; Yeung, R. C. Y.; Xia, H. J. Organomet. Chem. 1997, 538, 31.
10.1021/om0493659 CCC: $30.25 © 2005 American Chemical Society Publication on Web 01/13/2005
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Notes
Scheme 1
Figure 1. Molecular structure of [RuCl(CO)(PMe3)3]2(µCHdCHCHdCHCHdCHCHdCHCHdCH) (6). Table 1. Crystal Data and Structure Refinement Details for 6 formula formula wt wavelength, Å cryst syst space group a, Å b, Å c, Å β, deg V, Å3 Z dcalcd, g cm-3 abs coeff, mm-1 F(000) θ range, deg index ranges
of RuHCl(CO)(PPh3)3 with the dialkyne (3E,5E,7E)HCtCCHdCHCHdCHCHdCHCtCH. The previously unknown dialkyne (3E,5E,7E)-HCt CCHdCHCHdCHCHdCHCtCH (3) was prepared by the route shown in Scheme 1. The Wittig reaction of (2E,4E)-Me3SiCtCCHdCHCHdCHCHO (1)15 with Me3SiCtCCH2PPh3Br in the presence of NaN(SiMe3)2 produced the precursor compound 2. Treatment of 2 with NaOH produced 3, which was isolated as a yellow solid. Compound 3 is thermally unstable and polymerized readily when stored at room temperature. Thus, it was used immediately after it was produced. The identity of compound 3 can be easily identified by NMR spectroscopy. In particular, the 1H NMR spectrum (in C6D6) showed one tCH signal at 2.88 ppm and three dCH signals at 5.30, 5.70, and 6.47 ppm; the 13C{1H} NMR spectrum (in C6D6) showed the acetylenic carbon signals at 81.5 and 82.8 ppm and the vinyl signals at 111.8, 133.6, and 142.3 ppm. Treatment of 3 with the ruthenium hydride complex RuHCl(CO)(PPh3)3 (4) in dichloromethane produced the insertion product [RuCl(CO)(PPh3)2]2(µ-CHdCHCHd CHCHdCHCHdCHCHdCH) (5), which can be isolated as a purple solid in 87% yield (Scheme 1). The complex has been characterized by NMR and elemental analysis. The 31P{1H} NMR spectrum (in CD2Cl2) showed a singlet at 29.3 ppm, the chemical shift of which is typical for RuCl(CHdCHR)(CO)(PPh3)2.10 In the 1H NMR spectrum (in CD2Cl2), the Ru-CH signal was observed at 8.11 ppm. Treatment of 5 with PMe3 produced the sixcoordinated complex [RuCl(CO)(PMe3)3]2(µ-CHdCHCHd CHCHdCHCHdCHCHdCH) (6). The PMe3 ligands in 6 must be meridionally coordinated to ruthenium, as indicated by the AM2 pattern 31P{1H} NMR spectrum. The presence of the (CH)10 chain is confirmed by the (15) Vicart, N.; Castet-Caillabet, D.; Ramondenc, Y.; Ple, G.; Duhamel, L. Synlett 1998, 411.
no. of rflns no. of indep rflns no. of data/restraints/params goodness of fit on F2 final R indices (I > 2σ(I)) largest diff peak and hole, e Å-3
C30H64Cl2O2P6Ru2 915.67 0.71073 monoclinic P21/c 8.9468(11) 8.5865(5) 16.3021(10) 113.1590(10) 2438.4(3) 2 1.247 0.947 944 2.34-27.52 -24 e h e 24, -11 e k e 11, -21 e l e 21 26 628 5545 (R(int) ) 0.0348) 5545/0/190 0.999 R1 ) 0.0319, wR2 ) 0.0693 0.493 and -0.172
Table 2. Selected Bond Distances (Å) and Angles (deg) for 6a Ru(1)-C(10) Ru(1)-P(3) Ru(1)-P(2) O(1)-C(10) C(12)-C(13) C(14)-C(15)
1.815(3) 2.3565(7) 2.4048(7) 1.141(3) 1.441(3) 1.430(3)
C(10)-Ru(1)-C(11) C(11)-Ru(1)-P(3) C(11)-Ru(1)-P(1) C(10)-Ru(1)-P(2) P(3)-Ru(1)-P(2) C(10)-Ru(1)-Cl(1) P(3)-Ru(1)-Cl(1) P(2)-Ru(1)-Cl(1) C(12)-C(11)-Ru(1) C(14)-C(13)-C(12) C(15)#1-C(15)-C(14)
91.15(11) 80.99(6) 82.75(6) 88.61(8) 100.97(3) 179.22(8) 88.72(3) 90.93(2) 130.83(19) 124.7(3) 125.2(4)
Ru(1)-C(11) Ru(1)-P(1) Ru(1)-Cl(1) C(11)-C(12) C(13)-C(14) C(15)-C(15)#1
2.084(2) 2.3599(7) 2.4798(6) 1.336(3) 1.344(3) 1.334(5)
C(10)-Ru(1)-P(3) C(10)-Ru(1)-P(1) P(3)-Ru(1)-P(1) C(11)-Ru(1)-P(2) P(1)-Ru(1)-P(2) C(11)-Ru(1)-Cl(1) P(1)-Ru(1)-Cl(1) O(1)-C(10)-Ru(1) C(11)-C(12)-C(13) C(13)-C(14)-C(15)
91.98(8) 93.37(8) 162.97(3) 178.04(6) 95.31(3) 89.30(7) 86.04(3) 179.2(3) 125.4(2) 125.2(3)
a Symmetry transformations used to generate equivalent atoms: (#1) -x, -y + 2, -z.
1H
NMR spectrum (in CD2Cl2), which showed the vinyl proton signals at 8.05 (Ru-CH), 6.89 (β-CH), 6.54 (γ,δCH), and 6.30 (-CH) ppm. The structure of 6 has been confirmed by an X-ray diffraction study. The molecular structure of complex 6 is depicted in Figure 1. The crystallographic details and selected bond distances and angles are given in Tables 1 and 2, respectively. As shown in Figure 1, the compound contains two ruthenium centers linked symmetrically by a linear (CH)10 bridge with an inversion center at the midpoint of the C15-C15A bond. The geometry around ruthenium can be described as a distorted octahedron with three meridionally bound
Notes
PMe3 ligands. The vinyl group is trans to the unique PMe3 ligand, and the chloride is trans to the CO, as suggested by the solution NMR data. The mutually trans PMe3 ligands are bent away from the unique PMe3 but toward the vinyl ligand, as reflected by P(1)-RuP(2) (95.31(3)°), P(3)-Ru-P(2) (100.97(3)°), C(11)-RuP(1) (82.75(6)°), and C(11)-Ru-P(3) (80.99(6)°) angles, probably due to the steric interaction between the PMe3 ligands. As in the complexes RuH(CHdCMeCO2Bu)(CO)(PPh3)316 and [RuCl(CO)(PMe3)3]2(µ-CHdCHCHd CHCHdCHCHdCH),10 the unique Ru-P(2) bond (2.4048(7) Å) of 6 is slightly longer than those of the mutually trans Ru-P bonds (2.3599(7) and 2.3565(7) Å), due to the strong trans influence of the vinyl ligand. The Ru-C and C(R)-C(β) bond distances of complex 6 are within the range of those reported for ruthenium vinyl complexes.17 The (CH)10 ligand shows a single/double carboncarbon bond alternation. All the olefinic double bonds are in a trans geometry. The formal double bonds have an average bond distance of 1.338 Å, and the formal single bonds have an average bond distance of 1.436 Å. The difference in the average single- and double-bond distances is 0.098 Å, which is similar to those in PhCHd CH(CHdCH)2CHdCHPh (0.092 Å)18 and [RuCl(CO)(PMe3)3]2(µ-CHdCHCHdCHCHdCHCHdCH) (0.099 Å).10 Like the complex [RuCl(CO)(PMe3)3]2(µ-CHd CHCHdCHCHdCHCHdCH),10 the vinyl group is also essentially coplanar with Cl-Ru-CO. The atoms Cl(1), Ru(1), C(10), O(1), C(11), and C(12) are in a plane with a maximum deviation from the least-squares plane of 0.096 Å for Ru(1). The carbon atoms of the (CH)10 chain and the ruthenium atoms are also essentially coplanar, with a maximum deviation from the leastsquares plane of 0.050 Å for C(15). The coplanarity of the vinyl group and CO is expected, because stabilization due to the π interaction of CO and vinyl with metal centers is maximized in such a conformation.19 Electrochemical Study. The cyclic voltammogram of complex 6 has been collected in dichloromethane containing 0.10 M n-Bu4NClO4 as the supporting electrolyte. As shown in Figure 2a, the cyclic voltammogram of 6 has two partially resolved oxidation waves at -0.004 and 0.089 V vs Ag/AgCl (or -0.225 and -0.132 V vs Fc/Fc+). These oxidation waves can be easily visualized when the primary voltammogram was convolved by the semiderivative method (Figure 2b). These two oxidation waves can be attributed to the formation of [(PMe3)3(CO)ClRu(CHdCH)5RuCl(CO)(PMe3)3]+ and [(PMe3)3(CO)ClRudCH(CHdCH)4CHdRuCl(CO)(PMe3)3]2+, respectively. The peak separation of the two oxidation waves for complex 6 is at 0.09 V. Observation of two oxidation waves for complex 6 may imply that the two metal centers can interact with each other. (16) Komia, S.; Ito, T.; Cowie, M.; Yamamoto, A.; Ibers, J. A. J. Am. Chem. Soc. 1976, 98, 3874. (17) See for example: (a) Torres, M. R.; Santos, A.; Perales, A. Ros, J. J. Organomet. Chem. 1988, 353, 221. (b) Romero, A.; Santos, A.; Vegas, A. Organometallics 1988, 7, 1988. (c) Lo´pez, J.; Romero, A.; Santos, A.; Vegas, A.; Echavarren, A. M.; Noheda, P. J. Organomet. Chem. 1989, 373, 249. (e) Alcock, N. W.; Hill, A. F.; Melling, R. P. Organometallics 1991, 10, 3898. (f) Wakatsuki, Y.; Yamazaki, H.; Kumegawa, N.; Satoh, T.; Satoh, J. Y. J. Am. Chem. Soc. 1991, 113, 9604. (18) Drenth, W.; Wiebenga, E. H. Acta Crystallogr. 1955, 8, 755. (19) Choi, S. H.; Bytheway, I.; Lin, Z.; Jia, G. Organometallics 1998, 17, 3974.
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Figure 2. (a) Cyclic voltammogram of 6 in 0.10 M n-Bu4NPF6/CH2Cl2 (Pt electrode, V vs Ag/AgCl, scan rate 10 mV/ s, 25 °C). (b) Corresponding semidifferential data of the primary voltammogram.
As one might expect, the peak separation of the oxidation waves of complex 6 is smaller than those reported for the (CH)4-bridged complex Cp(dppm)Fe(CHdCH)2Fe(dppm)Cp (0.44 V),4b the (CH)6-bridged complex (PMe3)3(CO)ClRu(CHdCH)3RuCl(CO)(PMe3)3 (0.38 V),9 and the (CH)8-bridged complex (PMe3)3(CO)ClRu(CHdCH)4RuCl(CO)(PMe3)3 (0.24 V).10 We noted that there is a sharp dropoff in the wave separation between (CH)8 and (CH)10 complexes relative to that between (CH)6 and (CH)8 complexes, although we are not clear about the reason. The smaller wave separation of complex 6 may suggest that the interaction of the metal centers is weak. However, it should be noted that the potential difference of a symmetrical bimetallic complex, which may exhibit parallel variations with electronic coupling parameters (Vab), is a thermodynamic quantity relating to the thermodynamic stability of mixed-valence species. It depends on a through-bridge electronic interaction as well as other factors.20 Summary. We have prepared bimetallic complexes with metal centers bridged by (CH)10. The structure of [RuCl(CO)(PMe3)3]2(µ-CHdCHCHdCHCHdCHCHd CHCHdCH) (6) has been confirmed by X-ray diffraction. An electrochemical study shows that the metal centers in the bimetallic complex 6 interact with each other. Experimental Section All manipulations were carried out at room temperature under a nitrogen atmosphere using standard Schlenk techniques, unless otherwise stated. Solvents were distilled under nitrogen from sodium-benzophenone (hexane, diethyl ether, THF, benzene) or calcium hydride (dichloromethane, CHCl3). The starting materials RuHCl(CO)(PPh3)321 and (2E,4E)(20) Roue´, S.; Lapinte, C.; Bataille, T. Organometallics 2004, 22, 2558 and references therein. (21) Ahmad, N.; Levison, J. J.; Robinson, S. D.; Uttley, M. F.; Wonchoba, E. R.; Parshall, G. W. Inorg. Synth. 1974, 15, 45.
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Organometallics, Vol. 24, No. 4, 2005
(TMS)CtCCHdCHCHdCHCHO15 were prepared according to literature methods. Microanalyses were performed by M-H-W Laboratories (Phoenix, AZ). 1H, 13C{1H}, and 31P{1H} NMR spectra were collected on a Bruker ARX-300 spectrometer (300 MHz). 1H and 13C NMR chemical shifts are relative to TMS, and 31P NMR chemical shifts are relative to 85% H3PO4. The assignments of 1H and 13C NMR data for the alkenyl groups are based on 2D NMR experiments. The electrochemical measurements were performed with a PAR Model 273 potentiostat. A three-component electrochemical cell was used with a glassy-carbon electrode as the working electrode, a platinum wire as the counter electrode, and a Ag/ AgCl electrode as the reference electrode. The cyclic voltammograms were collected at a scan rate of 10 mV/s in CH2Cl2 containing 0.10 M n-Bu4NPF6 as the supporting electrolyte. The primary voltammogram of 6 was convolved by the semiderivative method to provide clear visual resolution of the redox waves. The peak potentials reported were referenced to Ag/AgCl. The ferrocene/ferrocenium redox couple was located at 0.221 V under our experimental conditions. (3E,5E,7E)-(TMS)CtCCHdCHCHdCHCHdCHCt CTMS (2). To a slurry of (3-(trimethylsilyl)-2-propynyl)triphenylphosphonium bromide (0.82 g, 1.8 mmol) in THF (25 mL) was added NaN(TMS)2 (0.72 mL, 1.8 mmol, 2.5 M in THF). This mixture was stirred at room temperature for 30 min, after which a solution of (2E,4E)-(TMS)CtCCHdCHCHd CHCHO (0.29 g, 1.63 mmol) in THF (20 mL) was added via syringe, and the resulting solution was stirred for 1 h. Water (50 mL) was added, and the organic layer was separated. The aqueous layer was extracted with diethyl ether (3 × 30 mL). The combined organic layers were washed with brine, dried over MgSO4, filtered, and then concentrated. The residue was purified by column chromatography (silica gel, hexane) to give a bright yellow solid. Yield: 0.32 g, 72%. Anal. Calcd for C16H24Si2: C, 70.51; H, 8.88. Found: C, 70.67, H, 9.02. 1H NMR (300.13 MHz, CDCl3): δ 0.20 (s, 18 H, SiMe3), 5.68 (d, J(HH) ) 15.3 Hz, 2 H, dCH), 6.35 (m, 2 H, dCH), 6.64 (m, 2 H, d CH). 13C NMR (75.5 MHz, CDCl3): δ -0.37 (s, SiMe3), 99.2 (s, CtC), 104.2 (s, CtC), 112.6 (s, dCH), 133.9 (s, dCH), 141.8 (s, dCH). (3E,5E,7E)-HCtCCHdCHCHdCHCHdCHCtCH (3). A solution of (3E,5E,7E)-(TMS)CtCCHdCHCHdCHCHdCHCt CTMS (1.60 g, 5.87 mmol) in EtOH (20 mL) was added to a mixture of a sodium hydroxide aqueous solution (50%, 10 mL) and EtOH (80 mL). The resulting solution was stirred for 4 h. A 70 mL portion of the saturated aqueous solution of sodium chloride was added. The solution was extracted with 4 × 60 mL of ether. The solvent was removed to give a brown-yellow solid. Yield: 0.48 g, 65%. 1H NMR (300.13 MHz, CDCl3): δ 2.88 (s, 2 H, HCtC), 5.30 (d, J(HH) ) 15.4 Hz, 2 H, dCH), 5.70 (m, 2 H, dCH), 6.47 (m, 2 H, dCH). 13C{1H} NMR (75.47 MHz, CDCl3): δ 81.5 (s, HCtC), 82.8 (s, CtCH), 111.8 (s, d CH), 133.6 (s, dCH), 142.3 (s, dCH). [RuCl(CO)(PPh 3)2]2(µ-CHdCHCHdCHCHdCHCHd CHCHdCH) (5). To a suspension of RuHCl(CO)(PPh3)3 (3.50 g, 3.67 mmol) in CH2Cl2 (50 mL) was added dropwise a solution of (3E,5E,7E)-HCtCCHdCHCHdCHCHdCHCtCH (0.300 g, 2.38 mmol) in CH2Cl2 (30 mL). The reaction mixture was stirred for 30 min to give a red solution. The mixture was
Notes filtered through a column of Celite. The volume of the filtrate was reduced to ca. 10 mL under vacuum. Addition of hexane (80 mL) to the residue produced a purple solid, which was collected by filtration, washed with hexane, and dried under vacuum. Yield: 2.4 g, 87%. Anal. Calcd for C84H70Cl2O2P4Ru2: C, 66.89; H, 4.68. Found: C, 66.69; H, 4.80. 31P{1H} NMR (121.5 MHz, CD2Cl2): δ 29.3 (s). 1H NMR (300.13 MHz, CD2Cl2): δ 5.63 (m, 4 H, δ,-CH), 6.08 (m, 4 H, β,γ-CH), 7.447.76 (m, 60 H, PPh3), 8.11 (br d, J(HH) ) 12.7 Hz, 2 H, RuCH). [RuCl(CO)(PMe 3)3]2(µ-CHdCHCHdCHCHdCHCHd CHCHdCH) (6). To a solution of [RuCl(CO)(PPh3)2]2(µ-CHd CHCHdCHCHdCHCHdCHCHdCH) (0.50 g, 0.33 mmol) in CH2Cl2 (20 mL) was added a 5 mL THF solution of PMe3 (1.0 M, 5.00 mmol). The reaction mixture was stirred for 15 h. The volatile materials were removed under vacuum. The solid was redissolved in benzene (3 mL). Addition of hexane (40 mL) to the residue produced a pale yellow solid, which was collected by filtration, washed with hexane, and dried under vacuum. Yield: 0.20 g, 66%. Anal. Calcd for C30H64Cl2O2P6Ru2: C, 39.35; H, 7.05. Found: C, 38.82; H, 6.55. 31P{1H} NMR (121.5 MHz, C6D6): δ -20.8 (t, J(PP) ) 22.8 Hz), -8.95 (d, J(PP) ) 22.8 Hz). 1H NMR (300.13 MHz, C6D6): δ 1.16 (d, J(PH) ) 6.7 Hz, 18 H, PMe3), 1.21 (t, J(PH) ) 3.4 Hz, 36 H, PMe3), 6.30 (m, 2 H, -CH), 6.54 (m, 4 H, γ,δ-CH), 6.89 (m, 2 H, β-CH), 8.05 (m, 2 H, Ru-CH). Crystallographic Analysis for [RuCl(CO)(PMe3)3]2(µCHdCHCHdCHCHdCHCHdCHCHdCH) (6). Crystals suitable for X-ray diffraction were grown from a CH2Cl2 solution layered with diethyl ether. A yellow single crystal with approximate dimensions of 0.20 × 0.20 × 0.10 mm3 was mounted on a glass fiber for diffraction experiments. Intensity data were collected on a Bruker Apex CCD area detector at 100 K and were corrected by semiempirical methods from equivalents. The structure was solved by Patterson methods, expanded by difference Fourier syntheses, and refined by fullmatrix least squares on F2 using the Bruker SHELXTL (version 5.10) program package. The molecule is centrosymmetric with the inversion center at the midpoint of C15 and C15A; thus, the crystallographic asymmetric unit contains half of one molecule. All non-hydrogen atoms were refined anisotropically. The hydrogen atoms were introduced at their geometric positions and refined as riding atoms. Further crystallographic details are summarized in Table 1.
Acknowledgment. We acknowledge financial support from the Hong Kong Research Grants Council and the National Natural Science Foundation of China (No. 20242010). Supporting Information Available: Tables of bond distances and angles, atomic coordinates and equivalent isotropic displacement coefficients, and anisotropic displacement coefficients for [RuCl(CO)(PMe3)3]2(µ-CHdCHCHd CHCHdCHCHdCHCHdCH) (6); these data are also available as a CIF file. This material is available free of charge via the Internet at http://pubs.acs.org. OM0493659
